Today, many people use microwave ovens. A person can use one from nearly anywhere (e.g., at home, at work, at the store, etc.). One of the primary reasons for their popularity is because they can conveniently and safely heat food, including beverages. A microwave oven heats food by bombarding it with electromagnetic radiation in the microwave spectrum causing polarized molecules in the food's water content to oscillate back and forth, and thereby generate thermal energy. This microwave cooking process is also known as dielectric heating.
Despite their popularity, microwave ovens or, more specifically, microwave cooking has a number of problems. For instance, microwave cooking can result in food becoming dry, or partially or unevenly heated. In addition, the cooking time can be very long, and the food can lose its original taste after being heated in the microwave oven. The main cause of these problems is due to how the microwave oven heats food through oscillation.
Furthermore, it is commonly advised to avoid placing metal containers in a microwave oven because the electromagnetic waves cannot pass through the metal, unlike glass, plastic, and paper. There is also the possibility that the oscillation of the electromagnetic waves may produce a concentrated electric field at the edge of the metal object. If that edge is in close proximity with another metallic object, sparks may appear between the two objects because of that concentration.